This invention relates to an improved shield for a reentry vehicle, and particularly to one made of fused silica.
Present shields for atmospheric reentry vehicles make use of a low atomic number (Z) material. The low atomic number of the material guarantees good ablative properties and a low radar cross-section. However, heat shields of low atomic number do not provide effective protection against radiation bursts from hot nuclear devices. These recently developed nuclear devices have increased damage potential.
In order to protect reentry vehicles such as missiles from these new types of damage mechanisms, high atomic number constituents have to be incorporated into the structural shell of the missile.
Fused silica has excellent thermal shock resistance as well as good ablative properties and a high radar transmissivity. However, it is a low atomic number material and, as such, cannot be used as a shield.
Accordingly, it is the principal object of this invention to provide an improved shield for use in reentry vehicles, which shield will protect the vehicle from radiation damage, and which will also have improved ablation characteristics and improved microwave properties.
It is a particular object of this invention to provide such a shield made of fused silica.